Java

JSF (Java Server Faces)

• JavaServer Faces (JSF) is a Java web application framework intended to simplify development and integration of web-based user interfaces;
• JSF is part of the Java Enterprise Edition;
• JSF is a request-driven MVC web framework for constructing user interfaces using components;
• As a display technology, JSF 2 uses Facelets: previous versions (JSF 1.x) used JavaServer Pages (JSP) instead of facelets for its display technology;
• JSF is a standardized technology which was formalized in a specification through the Java Community Process. So, in order to code in JSF, you need to use an implementation of this specification (Mojarra is the reference implementation).

• Mojarra: is the JSF reference implementation, distributed by Oracle;
  It was previously named "Sun JSF Reference Implementation" (aka Sun JSF RI) until version 1.2_08;
  It's part of the Glassfish project;
   
• MyFaces: The Apache Foundation JSF implementation with Ajax components;

• What is Mojarra?
• Compare JSF implementations

• RichFaces: an open source Ajax-enabled component library for JavaServer Faces, hosted by JBoss. It allows easy integration of Ajax capabilities into enterprise application development.
• IceFaces: open-source, Java JSF extension framework and rich components, Ajax without JavaScript;
• many more;

• Managed Beans (aka "Backing Beans" or "Page Beans"): normal JavaBean classes annotated with @ManagedBean that will supply the faceletes views with properties (views access this properties through EL to gather information for display);
• A template-based component system: you no longer need to use the include directives used on JSP+Servlets;
• Built-in Ajax support: using <f:ajax /> (since JSF v2.0);
• Built-in support for bookmarking & page-load actions;
• Integration with the Unified Expression Language (EL), which is core to the function of JSF. Views may access managed bean fields and methods via EL: <my:component rendered="#{myBean.userLoggedIn}" />. This lets you separate presentation (facelets views) from busines logic (managed beans): facelets views will only contain declarative code (HTML; facelets components; EL placeholders) and use EL to call managed beans properties (managed beans are the only ones to contain Java code and responsible for all the logic);
• A default set of HTML and web-application specific UI components:  and you can use many of-the-shelf component libraries;
• A server-side event model : For dispatching events and attaching listeners to core system functionality, such as "Before Render Response" or "After Validation"
• State management, supporting: "request", "session", "application", "flash", and "view" scoped Java beans.
• Two XML-based tag libraries (core and html) for expressing a JavaServer Faces interface within a view template (can be used with both JSP or Facelets)

Facelets (aka: View templates or Facelets views)

DropDownList

• javax.faces.model.SelectItem: represents a single item in the list of supported items associated with a UISelectMany or UISelectOne component.
  Useful for example if you want the dropdownlist to have a value (like and id) and a label (some text) for each one.
  The constructor has many overloads, ex:
  SelectItem(Object value)         
  SelectItem(Object value, String label)         
  SelectItem(Object value, String label, String description, boolean disabled, boolean escape, boolean noSelectionOption)

<h:form>           
    <legend>Select Company:<br />                 
        <h:selectOneMenu value="#{myObject.companyId}">
            <f:selectItems value="#{companyOptions.companyNames}"/>
        </h:selectOneMenu>
    </legend>
    <h:commandButton value="submeter" action="#{myObject.controller()}" />
</h:form> 

@ManagedBean
public class MyObject {

    private Company selectedCompany; //will be set by the controller method after the form is submitted
    private int companyId; //this is the value set by the dropdown list

    /**
     * Used to submit the form
     * @return the destination page
     */
    public String controller() {
        DaoMock dao = new DaoMock();

        this.selectedCompany = dao.getCompanyById(companyId);
        return "resultado";
        //TODO: if companyNotFound return String for error page instead
    }
//setters/getters omitted. NOTE: selectedCompany only has get, no set - it will be set by the controller method

@ManagedBean
public class CompanyOptions {

    public List<SelectItem> getCompanyNames() {
        List<SelectItem> listOfItems = new ArrayList<>();
        DaoMock dao = new DaoMock();
        Company[] companyArray = dao.getCompanies();

        for (Company c : companyArray) {
            listOfItems.add(
                    new SelectItem(c.getId(),c.getNome()));
        }

        return listOfItems;
    }